Compilation error: Statement with no effect

Question

dspList_t *pDspMng = NULL;

for(pDspMng = SDSPMNG; pDspMng->mesfct != NULL && strcmp (pDspMng->mesfct, mesfct); pDspMng->prec);

INTdspmng.sc: In function 'WebCallback':
INTdspmng.sc:216:9: error: statement with no effect [-Werror=unused-value]
         for(pDspMng = SDSPMNG; pDspMng->mesfct != NULL && strcmp (pDspMng->mesfct, mesfct); pDspMng->prec);

This loop is still waiting for a new mesfct for that i make ";" after for, i want an infinite loop

What are dspList_t and SDSPMNG? Who updates mesfct? Another thread? — Jabberwocky
– Jabberwocky, Commented Jan 6, 2021 at 12:16
Your for loop does not make sense. You iterate but nothing changes from one iteration to the next. So, either you iterate only once (but without changing anything to anything) if the condition part is false, or you iterate forever without any side-effect, which is plain useless. — Renaud Pacalet
– Renaud Pacalet, Commented Jan 6, 2021 at 12:16
@Jabberwocky : dsplist_t is a structure and SDSPMNG is a pointer to structure and mesfct updates by a webserver — Embeded_developer
– Embeded_developer, Commented Jan 6, 2021 at 12:30
@slamamohamed please edit the question and put all relevant information into the question. Show the declaration of the relevant structs and tell us what this "web server" is. Is it a thread? This "webserver updating mesfect" sounds very fishy. — Jabberwocky
– Jabberwocky, Commented Jan 6, 2021 at 12:35

Sourav Ghosh · Accepted Answer · 2021-01-06 12:11:17Z

1

The pDspMng->prec is practically useless. You're computing the value but doing nothing with that value. You may want to store the value in some variable, maybe like pDspMng = pDspMng->prec

Also, the ; at the end of the for loop looks erroneous.

answered Jan 6, 2021 at 12:11

Sourav Ghosh

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4 Comments

Jabberwocky Over a year ago

pDspMng->prec is not only practically useless. It is just plain useless.

Embeded_developer Over a year ago

how can we browse a linked list ?

Embeded_developer Over a year ago

i make pDspMng = pDspMng->prec and the problem resolved

Sourav Ghosh Over a year ago

@Jabberwocky better wordings. :P

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